1. Field of the Invention
The instant disclosure relates to method, apparatus and kit for detecting presence of cancer in certain mammals. More specifically, the disclosure relates to a method and apparatus for detecting hemangiosarcoma in canines and felines.
2. Description of Related Art
Nearly half of all dogs over the age of ten die from cancer. Conventional data indicate that the sum total for canine and feline cancer-related claims in the year 2005 was just shy of 20,000. This incident rate of newly uncovered cancer is consistent with other data.
Cancers are malignant neoplasms (growth) that occur when cell-dividing brake mechanisms (the genes that keep growth in check) go awry. Causes of these gene malfunctions may be inherited or acquired. Some breeds of dog seem particularly predisposed to develop certain types of cancer. For example, studies have shown that the English Setter, Chihuahua, Miniature Poodle and Afghan Hound have a predisposition for invasive mammary gland cancers. Boxers, American Staffordshire Terriers, Chinese Shar-Pei and Boston Terriers have a predisposition to mast cell (deep skin cell) cancers. Bernese Mountain dogs are prone to malignant histocytosis, which is a cancer of the white blood cells. Unspayed female dogs (and those spayed late in life) are more susceptible to mammary gland cancers and un-neutered male dogs (especially those with retained testicle) are at risk for testicular cancer. Malignancies are generally diseases of older dogs.
Mixed breed dogs are not immune to the development of cancer; they can suffer from malignant skin tumors if they inherit a faulty brake gene from one parent. Acquired cancers arise when the cell mechanisms are disrupted by a virus (although rare in dogs), by irradiation (skin cancers on dogs with short coats and pale skin exposed to excessive sunlight), or by an accumulation of toxic chemicals, either from failure of a cell to dispose of its waste byproducts or from natural or manmade chemicals in the environment. Body type is also implicated in the development of some types of cancer. Large and giant dogs have a higher risk of the bone cancer osteosarcoma that is associated with stress on weight-bearing limbs and dogs with dark skin are susceptible to melanomas.
Statistical data show that the most common cancers in dogs are lymphoma (a cancer affecting the lymph node system), skin tumors and osteogenic sarcoma (bone cancer). The data also suggest that cats similarly suffer from lymphoma and skin tumors.
Hemangiosarcoma (“HSA”) is a malignant and rapidly growing cancer. HSA is difficult to detect. HSA is a tumor derived from blood vessels, and thus the tumor is filled with blood. A frequent cause of death from HSA is the rupturing of the tumor, causing the patient to rapidly hemorrhage to death. HSA in humans is commonly associated with toxic exposure to thorium dioxide (thorotrast), vinyl chloride and arsenic. The causes of HSA in dogs are largely unknown.
HSA is somewhat common on dogs, and more so in certain breeds of dogs such as German Shepherds and Golden Retrievers. HSA also occurs in cats, though it is rare. Dogs with HSA rarely show clinical signs until the tumor has become very large and has metastasized. Typically, clinical signs are due to hypovolaemia after the tumor ruptures, causing severe bleeding. Owners of the affected dogs often discover that the dog has HSA only after the animal has collapsed.
The HSA tumor often appears on the spleen, right heart base or liver. HSA is the most common tumor of the heart and it occurs in the right atrium, where it can cause right-heart failure, arrhythmias, pericardial effusion and cardiac tamponade. HSA of the spleen or liver is the most common tumor to cause hemorrhage in the abdomen.
The success of treatment to cure cancer lies in early detection of the disease. However, early detection of HSA is one of the most challenging aspects of the disease. This is primarily because HSA most commonly develops internally, where it is not easily noticed and examined. In many instances, malignant tumors arising in the organs of body will eventually cause symptoms directly related to the location of the tumor. A wait-and-see method to diagnose HSA is inappropriate since by the time the cancer is large enough to detect, it has already reached an advanced stage and is unlikely to respond favorably to treatment.
There are currently no commercially viable screening mechanisms for detecting HSA in dogs. Most dogs present with HSA as emergencies and major decisions about treatment must be made without a definitive diagnosis. A screening test that would allow the detection of HSA would be very valuable in the planning of treatment and earlier detection of the disease. Thus, there is a need for a method, apparatus and kit for early detection of HSA.